In-plane thermal diffusivity estimation by radial fin method

Abstract

This work presents a methodology to estimate the in-plane thermal diffusivity through infrared thermography. Experimentally, a vertical thin-thickness sample is briefly heated on its center by Joule effect and one face is filmed by an infrared camera. The experimental temperature field is compared with an analytical axisymmetric semi-infinite thermal model. The in-plane thermal diffusivity and a modified Biot number are estimated through a least square method based on the minimization of the quadratic error between the experimental and the theoretical temperatures. The methodology is applied to four samples with a broad range of thermal conductivity: balsa, PVC, mild steel, and aluminum alloy. The analysis of the residuals and of the parameter correlation coefficients show the feasibility of the method for isotropic materials for which a rather good agreement with literature data is found. When applied to anisotropic materials like balsa, the method shows the possibility with one experiment to characterize in every material directions.